1. Field of the Invention
This invention relates to lubricant compositions and more particularly to water-soluble lubricant compositions adapted for use as lubricants and coolants in metal machining operations.
2. Description of the Prior Art
In machining operations of metals, such as cutting, grinding, turning, milling and the like, it is customary to flood the tool and the work with a coolant for the purpose of carrying off heat which is produced during the operation. It is also customary to employ these coolants in combination with various agents having lubricating and extreme-pressure properties for reducing friction between the tool and work piece, particularly in operations such as tapping and broaching. In this respect, it has, heretofore, been the practice to employ for such purpose aqueous compositions containing such lubricating agents as emulsified petroleum or non-petroleum additives. Such aqueous cutting fluids, in order to perform satisfactorily, should meet certain important requirements.
Among the requirements for a satisfactory cutting fluid are corrosion-inhibiting properties for ferrous and cuprous alloys, and also stability under the conditions of operation. While various cutting fluids may possess such characteristics, there are, however, further important requirements that should also be met. Among these requirements is the ability to avoid leaving deposits on the tool and the work following the machining operation which result from subsequent drying of the fluid and which are difficult to remove. Other important requirements include tolerance in hard water solutions so that the precipitation of lubricant components will not occur, avoidance of tacky residues which interfere with the operation of the machine and avoidance of excessive foam formation. Cutting fluids known prior to this invention have not, however, satisfactorily met all of the foregoing requirements.
U.S. Pat. No. 3,374,171 teaches lubricants for metal working that contain alkanolamine polyoxyalkylene glycol and a saturated organic acid having 6 to 9 carbon atoms.